Recoil absorber

ABSTRACT

A recoil absorber for a firearm having a shoulder stock. A sleeve member is telescopically mounted at the rear end of the stock and attached to the end of at least one piston rod which is connected to a piston slidably disposed in a cylinder. The cylinder is mounted in the butt end of the stock and is sealingly closed at its forward end. A spring is mounted between the forward end and the piston. The piston rod projects rearwardly through a relatively long bore hole in the rear wall of the cylinder and the rod side of said piston and cylinder is vented to the atmosphere through a hole in the rear wall.

[ Jan.2,1973

[54] REUOIL ABSQRBE Kenneth Ruth, PD. Box 7039, Corpus Christi, Tex. 78409 [22] Filed: Nov. 18, 1970 [21] Appl. No.: 90,690

[76] Inventor:

[52] US. Cl .42/74 [51] Int. Cl. ..F41c 23/00 [58] Field of Search ..'...42/74 [56] References Cited H V UNITED STATES PATENTS 3,039,222 6/1962 Hoge ..42/74 1,964,649 6/1934 Stetson.... ..42/74 837,60l 12/1906 Behr ..42/74 3,l76,424 4/1965 Hoge ..42/74 Primary Examiner-Benjarnin A. Borchelt Assistant Examiner-C. T. Jordan Attorney-Carlos A. Torres [5 7] ABSTRACT A recoil absorber for a firearm having a shoulder stock. A sleeve member is telescopically mounted at the rear end of the stock and attached to the end of at least one piston rod which is connected to a piston slidably disposed in a cylinder. The cylinder is mounted inflthe butt end of the stock and is sealingly closed at its forward end. A spring is mounted between the forward end and the piston. The piston rod projects rearwardly through a relatively long bore hole in the rear wall of the cylinder and the rod side of said piston and cylinder is vented to the atmosphere through a hole in the rear wall.

10 Claims, 3 Drawing Figures PATETED JW 2 1975 3 7' 07 797 F/GZ i Kenneth Ruth INVEN TOR A T TORNEY Riscon. ABSORBER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to firearms. More specifically, it concerns recoil absorbing apparatus for shoulder fired guns, such as rifles and shotguns.

2. Description of the Prior Art It is well known that the discharge of firearms produces a recoil or kick. This is particularly and sometimes painfully noticeable in shoulder fired guns. Many attempts have been made to reduce the effect of such recoil by providing recoil absorbing mechanisms. A few of the more recent developments are shown in the following U. S. Patents: U. S. Pat. No. 3,019,543 A. Ducharme; U. S. Pat. No. 3,039,222 R. O. I-Ioge; and, U. S. Pat. No. 3,233,354 J. M. Ahearn.

Most recoil absorbing apparatus, presently in use, employ cylinder and piston arrangements whereby a compressible fluid is compressed in the cylinder by the piston when the firearm is discharged. Most such arrangements are relatively complicated, expensive and require the introduction and maintenance of a compressible fluid in the cylinder. Also, in most pistoncylinder arrangements, either a tight seal is provided around the piston rod or the entire rod side of the piston is fully opened to atmospheric pressure. In the first case, the rate of firing permissible is reduced due to compression taking place on the rod side of the piston during the rearward or return stroke. In the second case, no resistance is provided to the return stroke, resulting in a sudden jarring stop. Although this perhaps does not affect the shoulder so much as recoil, it is equally disturbing to the aim and general composure of the gun user in rapid fire. Furthermore, with the piston-cylinder arrangements presently in use a relatively long and somewhat cumbersome butt piece or sleeve member is required to prevent misalignment of the pistons.

SUMMARY OF THE INVENTION The present invention comprises a piston and cylinder arrangement, which has the advantage of other recoil apparatus. It is more simple and less costly than most. It employs a less expensive butt piece. In addition, it provides means for presenting enough resistance to the return piston stroke to eliminate disturbance of the gun user, but not enough resistance to materially affect the maximum rate of fire.

BRIEF DESCRIPTION OF THE DRAWING For a detailed description of the invention, reference will be made to the drawings in which:

FIG. 1 is an elevation view of the stock end of a shoulder firearm showing the exterior of a preferred embodiment of the invention in firing or rest position,

FIG. 2 is an elevation view of the stock end of a firearm as in FIG. 1, in section to show the arrangement of recoil apparatus according to a preferred embodiment of the invention, and

FIG. 3 is detailed elevation view, in section, showing an alternate embodiment of the invention.

2 DESCRIPTION OF A PREFERRED EMBODIMENT With reference to the drawings, the stock 10 of a conventional shoulder firearm is shown with a recoil sleeve or butt piece 12 telescopically mounted thereon. Obviously, the sleeve 12 rests against the shoulder of the user and telescopically receives the rear part of stock 10 on firing recoil.

Mounted in cylindrical holes at the rear of stock 10 are a pair of tubular cylinders 20, closed at the forward end by sealed plugs 22, which may be threadingly connected thereto. The rearward end of cylinders 20 may be threadingly connected to a mounting or base plate 24. Base plate 24 is in turn fastened to the butt of stock 10 in any suitable fashion, e.g., screws 26.

Mounted for sliding longitudinal movement in each cylinder 20 is a piston 30 and piston rod 32. The internal diameter of cylinders 20 are reduced near plate 24 to provide a rear wall 33 to sleeve 12. Sleeve 12 may be provided with counter sunk holes for receiving screws 36, attaching the ends of rods 32 to sleeve 12. Washers 38 of a diameter larger than rods 32 may be placed between rods 32 and sleeve 12. Corresponding counterbores 40, in the rearward end of cylinder 20, may be provided to receive washers 38 on extreme recoil for absorbing some shock and acting as a safety feature.

Bore holes 34 are of a substantial length to provide bearing and alignment surface for rods 32. By having them of such length it eliminates the necessity of a close tolerance between sleeve 12 and stock 10 and reduces the required length of sleeve 12. The exact length of bore hole 34 is dependent, among other things, on tolerances between rods 32 and their respective bore holes 34 and relative diameters of cylinders 20, pistons 30 and rods 32. However, a good rule of thumb is that the length should be equal to at least 3 times the diameter of rods 32.

A vent hole 42 through the heavy wall portion of cylinders 20 surrounding bore holes 34 provides communication between the atmosphere and the interior of cylinders 20 on the rod side of piston 30. The purpose of these holes 42 will be more fully understood hereafter.

Pistons 30 are provided with seals, such as O-rings 44, to sealingly engage the wall of cylinders 20. Smaller O-rings 46 may be placed around rods 32 to act as cushions on return from recoil. Springs 48 may be placed between pistons 30 and plugs 22, biasing the sleeve 12 and pistons 30 toward the normal firing position shown in FIG. 2.

When held against the shoulder for firing, the recoil apparatus of the invention rests in the position of FIG. 2. On firing, the butt of stock 10 recoils toward and is telescopically further received within sleeve 12. The air in the piston head side of cylinders 20 and springs 48 are compressed as pistons 30 move forward, absorbing the shock of recoil. At the same time, a certain amount of air enters the rod side area of cylinders 20 vacated by piston 30. After the piston 30 reaches its furthermost forward position, on firing, the compressed air and springs 48 begin to expand, forcing pistons 30 and consequently sleeve 12 back toward the normal position of FIG. 2. Since a certain amount of air has entered the rod side of cylinders 20 through vent holes 42, this air is again forced out through holes 42. Since these holes 42 are relatively small, the air is compressed until enough has escaped to return to atmospheric pressure. Thus the return to normal position is also cushioned. As previously pointed out, O-rings 46 may also cushion the final travel.

An alternate embodiment of the invention is shown in FIG. 3. In addition to the vent hole or conduit 42, another conduit 52 is provided in the heavy wall portion of cylinder 20 surrounding bore holes 34. A check valve 54 is placed in the conduit 52 to allow air to enter conduit 52 during recoil, but to prevent flow through conduit 52 on the return stroke of piston 30. Thus, two conduits 42 and 52 allow air to enter the rod side of cylinder 20 during recoil, but only one vent hole 42 allows air to escape during the return stroke. Therefore, the air is not allowed to escape as fast as it enters, resulting in compression of the air and further cushioning of the return stroke.

7, Although only two embodiments utilizing two pistons and cylinders have been shown, it is obvious that one or more pistons and cylinders may be used and that many variations of the invention may be made by one skilled in art without departing from the spirit of the invention. The form of the specification and drawings is for purposes of illustration and better understanding of the invention and not limiting its scope, the scope being limited only by the claims which follow.

I claim:

1. Recoil absorbing apparatus for a firearm comprismg:

a shoulder contacting member mounted on the rear of a firearm stock; at least one tubular cylinder mounted at the end of said stock with its longitudinal axis extending generally forwardly and rearwardly of said firearm, the forward end of said cylinder being sealingly closed; a piston slidably disposed in and sealingly engaging said cylinder; a piston rod projecting through a bore hole in a wall at the rear of said cylinder and connecting said piston to said shoulder contacting member: and conduit means through said wall venting the rod end of said piston to atmospheric pressure.

2. Recoil absorbing apparatus as set forth in claim 1, characterized in that the length of said bore hole is at least 3 times the diameter of said piston rod.

3. Recoil absorbing apparatus as set forth in claim 1, characterized in that said conduit means comprises first and second vent holes, at least one of which is provided with a check valve permitting flow into said cylinder through its respective vent hole, but preventing flow in the opposite direction.

4. Recoil absorbing apparatus as set forth in claim 1, characterized by a resilient annular cushion member surrounding said rod adjacent said piston to cushion shocks when said piston moves in a rearwardly direction.

5. Recoil absorbing apparatus as set forth in claim 4, characterized in that a washer of a diameter larger than said rod is mounted between the rear end of said rod and said shoulder contacting member and in that the said wall at the rear of said cylinder is counterbored to receive said washer on extreme forward movement of said piston.

6. Recoil absorbing apparatus as set forth in claim 1, characterized by a spring member mounted in said cylinder between the forward end of said cylinder and said piston, biasing said piston toward the rear of said cylinder.

7. Recoil absorbing apparatus as set forth in claim 6, characterized in that said bore hole surrounds said rod in a close sliding but nonsealing fit, the length of said bore hole being at least three times the diameter of said rod. 7

8. Recoil absorbing apparatus as set forth in claim 7, characterized by a resilient annular cushion member surrounding said rod adjacent said piston and engageable with said wall on extreme rearward movement of said piston to absorb shock of such movement.

9. Recoil absorbing apparatus as set forth in claim 8, characterized in that said cylinder is threadingly attached at its rearward end to a plate member which is attached to the butt of said stock and the forward end of said cylinder is closed by a removable plug to allow the removal of said piston. I

10. Recoil absorbing apparatus for a firearm comprising:

a shoulder contacting member mounted on the rear of a firearm stock; at least one tubular cylinder mounted at the end of said stock with its longitudinal axis extending generally forwardly and rearwardly of said firearm, the forward end of said cylinder being sealingly closed; a piston slidably disposed in and sealingly engaging said cylinder; and a piston rod projecting through a bore hole in a wall at the rear of said cylinder and connecting said piston to said shoulder contacting member; characterized by a resilient annular cushion member surrounding said rod adjacent said piston to cushion shocks when said piston moves in a rearwardly direction. 

1. Recoil absorbing apparatus for a firearm comprising: a shoulder contacting member mounted on the rear of a firearm stock; at least one tubular cylinder mounted at the end of said stock with its longitudinal axis extending generally forwardly and rearwardly of said firearm, the forward end of said cylinder being sealingly closed; a piston slidably disposed in and sealingly engaging said cylinder; a piston rod projecting through a bore hole in a wall at the rear of said cylinder and connecting said piston to said shoulder contacting member; and conduit means through said wall venting the rod end of said piston to atmospheric pressure.
 2. Recoil absorbing apparatus as set forth in claim 1, characterized in that the length of said bore hole is at least 3 times the diameter of said piston rod.
 3. Recoil absorbing apparatus as set forth in claim 1, characterized in that said conduit means comprises first and second vent holes, at least one of which is provided with a check valve permitting flow into said cylinder through its respective vent hole, but preventing flow in the opposite direction.
 4. Recoil absorbing apparatus as set forth in claim 1, characterized by a resilient annular cushion member surrounding said rod adjacent said piston to cushion shocks when said piston moves in a rearwardly direction.
 5. Recoil absorbing apparatus as set forth in claim 4, characterized in that a washer of a diameter larger than said rod is mounted between the rear end of said rod and said shoulder contacting member and in that the said wall at the rear of said cylinder is counterbored to receive said washer on extreme forward movement of said piston.
 6. Recoil absorbing apparatus as set forth in claim 1, characterized by a spring member mounted in said cylinder between the forward end of said cylinder and said piston, biasing said piston toward the rear of said cylinder.
 7. Recoil absorbing apparatus as set forth in claim 6, characterized in that said bore hole surrounds said rod in a close sliding but nonsealing fit, the length of said bore hole being at least three times the diameter of said rod.
 8. Recoil absorbing apparatus as set forth in claim 7, characterized by a resilient annular cushion member surrounding said rod adjacent said piston and engageable with said wall on extreme rearward movement of said piston to absorb shock of such movement.
 9. Recoil absorbing apparatus as set forth in claim 8, characterized in that said cylinder is threadingly attached at its rearward end to a plate member which is attached to the butt of said stock and the forward end of said cylinder is closed by a removable plug to allow the removal of said piston.
 10. Recoil absorbing apparatus for a firearm comprising: a shoulder contacting member mounted on the rear of a firearm stock; at least one tubular cylinder mounted at the end of said stock with its longitudinal axis extending generally forwardly and rearwardly of said firearm, the forward end of said cylinder being sealingly closed; a piston slidably disposed in and sealingly engaging said cylinder; and a piston rod projecting through a bore hole in a wall at the rear of said cylinder and connecting said piston to said shoulder contacting memBer; characterized by a resilient annular cushion member surrounding said rod adjacent said piston to cushion shocks when said piston moves in a rearwardly direction. 